Absorbent products such as industrial wipers, food service wipers, and other similar items are designed to combine several important attributes. For example, the products should have good bulk, a soft feel and should be highly absorbent. The products should also have good strength even when wet and should resist tearing. Further, the wiping products should have good stretch characteristics, should be abrasion resistant and should not deteriorate in the environment in which they are used.
In the past, many attempts have been made to enhance and increase certain physical properties of wiping products, especially wiping products that contain a large proportion of pulp or paper. Unfortunately, however, when steps are usually taken to increase one property of a wiping product, other characteristics of the product may be adversely affected. For instance, in pulp fiber based wiping products, softness and bulk can be increased by decreasing or reducing interfiber bonding within the paper web. Inhibiting or reducing fiber bonding by chemical and/or mechanical debonding, however, adversely affects the strength of the product. A challenge encountered in designing pulp based wiping products is increasing softness, bulk and texture without decreasing strength and/or abrasion resistance.
One particular process that has proven to be very successful in producing paper towels and other wiping products is disclosed in U.S. Pat. No. 3,879,257 to Gentile, et al., which is incorporated herein by reference in its entirety. In Gentile, et al., a process is disclosed for producing soft, absorbent, single ply fibrous webs having a laminate-like structure.
The fibrous webs disclosed in Gentile, et al. are formed from an aqueous slurry of principally lignocellulosic fibers under conditions which reduce interfiber bonding. A bonding material, such as a latex elastomeric composition, is applied to a first surface of the web in a spaced-apart pattern. The bonding material provides strength to the web and abrasion resistance to the surface.
The bonding material can then be similarly applied to the opposite side of the web for further providing additional strength and abrasion resistance. Once the bonding material is applied to the second side of the web, the web can be brought into contact with a creping surface. Specifically, the web will adhere to the creping surface according to the pattern by which the bonding material was applied. The web is then creped from the creping surface with a doctor blade. Creping the web mechanically debonds and disrupts the fibers within the web, thereby increasing the softness, absorbency, and bulk of the web.
In one alternative embodiment disclosed in Gentile, et al., both sides of the paper web are creped after the bonding material has been applied.
Although this technology has been applied to paper products, it has not been tried with composites having a fibrous component and a continuous filament component that reinforces and strengthens the material. One disadvantage of the embodiments disclosed in Gentile, et al. is that the bonding material is generally cured or dried at high temperatures that degrade the continuous filaments.
Composite materials, which desirably combine pulp and a nonwoven layer of substantially continuous filaments, have desirable levels of strength but often exhibit poor tie-down of the fibrous component. That is, the fibrous material and/or any fiber rich surfaces tends to be weaker is than the continuous filament component. This can cause undesirable levels of Tinting, poor abrasion resistance and may yield a material that has less overall strength. Attempts to soften and/or increase the bulk of these composite materials can disrupt the tie-down or bonding of the fibrous material.
Thus, there currently remains a need for a pulp based wiping product that includes a continuous filament substrate. A need also exists for a pulp based wiping product incorporating a continuous filament substrate and having improved softness over conventional products while still remaining strong. A need further exists for a pulp based wiping product incorporating a continuous filament substrate that does not become compressed when wet and has the tactile aesthetics of a textile during use.